api/msgpack-rpc: Improve error infrastructure

- Add error type information to `Error`
- Rename `set_api_error` to `api_set_error` for consistency with other api_*
  functions/macros.
- Refactor the api_set_error macro to accept formatted strings and error types
- Improve error messages
- Wrap error messages with gettext macro
- Refactor msgpack-rpc serialization to transform Error instances into [type,
  message] arrays
- Add error type information to API metadata
- Normalize nvim->client and client->nvim error handling(change
  channel_send_call to accept an Error pointer instead of the `errored` boolean
  pointer)
- Use macro to initialize Error structures

1 files changed, 8 insertions, 1 deletions

diff --git a/src/nvim/api/private/defs.h b/src/nvim/api/private/defs.h
index 2dd229ec5f..76ac23a521 100644
--- a/src/nvim/api/private/defs.h
+++ b/src/nvim/api/private/defs.h
@@ -8,6 +8,7 @@
 #define ARRAY_DICT_INIT {.size = 0, .capacity = 0, .items = NULL}
 #define STRING_INIT {.data = NULL, .size = 0}
 #define OBJECT_INIT { .type = kObjectTypeNil }
+#define ERROR_INIT { .set = false }
 #define REMOTE_TYPE(type) typedef uint64_t type
 
 #ifdef INCLUDE_GENERATED_DECLARATIONS
@@ -16,8 +17,14 @@
 #endif
 
 // Basic types
+typedef enum {
+  kErrorTypeException,
+  kErrorTypeValidation
+} ErrorType;
+
 typedef struct {
-  char msg[256];
+  ErrorType type;
+  char msg[1024];
   bool set;
 } Error;